Fuel pressure regulators of the type to which the invention relates comprise a control chamber to which intake manifold vacuum is communicated. A vacuum port is provided on the fuel pressure regulator housing for the control chamber so that a conduit through which the vacuum is conveyed can be connected to the fuel pressure regulator. Various embodiments of fuel pressure regulators typically include one of the following three constructions for the vacuum port.
In a first construction, the vacuum port is formed integrally with a metal housing cover by a deep drawing process. This approach is reliable and cost-efficient, but can be used only when the vacuum port is a straight tube that is parallel to the main axis of the regulator. Commonly assigned U.S. Pat. Nos. 5,076,320 and 5,163,468 disclose fuel pressure regulators embodying this construction. Unfortunately, it is not possible to use this approach when the vacuum port must be non-parallel to the regulator main axis, such as when the vacuum port is in a radially facing portion of the cover like the cover's sidewall, or else when it contains a bend.
In a second construction, the vacuum port is a separate metal fitting that is assembled to a metal housing cover by a procedure such as brazing. This construction is more costly than the first due to the fact that there are two separate parts (the cover and the fitting) that must be processed and the fact that a brazing operation must be conducted. When the fitting must be located in the cover sidewall, the process of joining the cover to the base of the housing is made more complicated since the fitting must be brazed to the cover before the cover is joined to the base, and the presence of the fitting on the cover can be accommodated only by using more complicated tools to join the cover and base.
A third construction is like the second except that a metal spin welding process, rather than brazing, is used.
The present invention relates to a new and unique pressure regulator of the aforementioned type which allows the vacuum port to be an injection-molded part made of suitable plastic and readily mounted on a housing cover by means of relatively inexpensive equipment. The parts, equipment, and the process are cost-efficient. Principles of the invention enable a variety of different port configurations to be realized, and often to be used with a common housing cover. The various features, advantages, and benefits of the invention will appear in the ensuing detailed description of a presently preferred embodiment, which concludes with a number of claims defining the inventive principles. The description is accompanied by a drawing which discloses the best mode contemplated at this time for carrying out the invention.